Helleborus plant named ‘NVDH 100’

ABSTRACT

A new and distinct cultivar of  Helleborus  plant named ‘NVDH 100’, characterized by its upright and mounding plant habit; uniform and freely flowering habit; dark green-colored leaves; double white and yellow green-colored flowers; and good garden performance.

Botanical designation: Helleborus×hybridus.

Cultivar denomination: ‘NVDH 100’.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar of Helleborus plant, botanically known as Helleborus×hybridus and hereinafter referred to by the name ‘NVDH 100’.

The new Helleborus plant is a product of a planned breeding program in Maastricht, The Netherlands. The objective of the breeding program was to create new uniform Helleborus plants with unique leaf and flower coloration and resistance to pathogens and pests.

The new Helleborus plant originated from a cross-pollination conducted by the Inventor in Maastricht, The Netherlands in February, 1997 of two unnamed proprietary seedling selections of Helleborus×hybridus, not patented. The new Helleborus plant was discovered and selected by the Inventor as a single flowering plant from within the progeny of the stated cross-pollination grown in a controlled greenhouse environment in Maastricht, The Netherlands in March, 1999.

Asexual reproduction of the new Helleborus plant by divisions in a controlled greenhouse environment in Maastricht, The Netherlands since November, 2002 has shown that the unique features of this new Helleborus plant are stable and reproduced true to type in successive generations.

SUMMARY OF THE INVENTION

Plants of the new Helleborus have not been observed under all possible environmental conditions and cultural practices. The phenotype may vary somewhat with variations in environmental conditions such as temperature and light intensity without, however, any variance in genotype.

The following traits have been repeatedly observed and are determined to be the unique characteristics of ‘NVDH 100’. These characteristics in combination distinguish ‘NVDH 100’ as a new and distinct Helleborus plant:

-   -   1. Upright and mounding plant habit.     -   2. Uniform and freely flowering habit.     -   3. Dark green-colored leaves.     -   4. Double white and yellow green-colored flowers.     -   5. Good garden performance.

Compared to plants of the parent selections, plants of the new Helleborus are more uniformly mounded and are more freely flowering.

Plants of the new Helleborus can be compared to plants of Helleborus orientalis ‘HLR 160’, disclosed in U.S. Plant Pat. No. 21,504. In side-by-side comparisons conducted in Maastricht, The Netherlands, plants of the new Helleborus differed from plants of ‘HLR 160’ in the following characteristics:

-   -   1. Plants of the new Helleborus had double-type flowers whereas         plants of ‘HLR 160’ had single-type flowers.     -   2. Plants of the new Helleborus and ‘HLR 160’ differed in flower         color as plants of ‘HLR 160’ had white and greyed purple         bi-colored flowers.

Plants of the new Helleborus can also be compared to plants of Helleborus orientalis ‘HLR 180’, disclosed in U.S. Plant Pat. No. 22,020. In side-by-side comparisons conducted in Maastricht, The Netherlands, plants of the new Helleborus differed from plants of ‘HLR 180’ in the following characteristics:

-   -   1. Plants of the new Helleborus had double-type flowers whereas         plants of ‘HLR 180’ had single-type flowers.     -   2. Plants of the new Helleborus and ‘HLR 180’ differed in flower         color as plants of ‘HLR 180’ had white-colored flowers with red         purple-colored central spots.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

The accompanying colored photographs illustrate the overall appearance of the new Helleborus plant showing the colors as true as it is reasonably possible to obtain in colored reproductions of this type. Colors in the photographs may differ slightly from the color values cited in the detailed botanical description which accurately describe the colors of the new Helleborus plant.

The photograph on the first sheet comprises a side perspective view of a typical flowering plant of ‘NVDH 100’ grown in a container.

The photograph on the second sheet is a close-up view of a typical flower of ‘NVDH 100’.

DETAILED BOTANICAL DESCRIPTION

The aforementioned photographs and following observations, measurements and values describe plants grown during the autumn in 15-cm containers in a glass-covered greenhouse in Glandorf, Germany and under cultural practices typical of commercial Helleborus production. During the production of the plants, day temperatures ranged from 12° C. to 32° C. and night temperatures ranged from 3° C. to 18° C. Plants were 14 months old when the photographs and the description were taken. In the following description, color references are made to The Royal Horticultural Society Colour Chart, 2007 Edition, except where general terms of ordinary dictionary significance are used.

-   Botanical classification: Helleborus hybridus ‘NVDH 100’. -   Parentage:     -   -   Female, or seed, parent.—Unnamed proprietary seedling             selection of Helleborus×hybridus, not patented.         -   Male, or pollen, parent.—Unnamed proprietary seedling             selection of Helleborus×hybridus, not patented. -   Propagation:     -   -   Type.—By tissue culture.         -   Time to initiate roots, winter.—About two months at 12° C.         -   Time to produce a rooted young plant, winter.—About six             months at 4° C. to 15° C.         -   Root description.—Thick to thin, fleshy; white to brown in             color.         -   Rooting habit.—Sparse. -   Plant description:     -   -   Plant and growth habit.—Herbaceous perennial; upright and             mounding plant habit with flowers held above the foliar             plane; plant shape is roughly broadly ovate; moderately             vigorous growth habit.         -   Plant height.—About 31.6 cm.         -   Plant diameter (area of spread).—About 34.4 cm. -   Leaf description:     -   -   Arrangement.—Leaves arranged alternately in a basal rosette;             leaves palmately compound with about five leaflets per leaf.         -   Leaf length.—About 19.3 cm.         -   Leaf width.—About 20.1 cm.         -   Leaflet length.—About 12.5 cm.         -   Leaflet width.—About 5.4 cm.         -   Leaf shape.—Palmate; orbicular in outline.         -   Leaflet shape.—Broadly elliptic to obovate.         -   Leaflet apex.—Acute to broadly acute.         -   Leaflet base.—Cuneate.         -   Leaflet margin.—Sharply serrate; somewhat undulate.         -   Leaflet texture, upper and lower surfaces.—Smooth, glabrous;             leathery.         -   Leaflet venation pattern.—Pinnate.         -   Leaflet color.—Developing leaves, upper surface: Close to             137A. Developing leaves, lower surface: Close to 146B. Fully             developed leaves, upper surface: Darker than between N137A             and 147A; venation, close to 144B tinged at the leaf base             with close to 200B to 200C. Fully developed leaves, lower             surface: Close to 147A to 147B; venation, close to 145A to             145B.         -   Petioles.—Length: About 14.4 cm. Diameter: About 5 mm.             Texture, upper and lower surfaces: Smooth, glabrous. Color,             upper and lower surfaces: Close to 143B; at the base, close             to N186C and 200B. -   Flower description:     -   -   Flower shape and habit.—Double-type rotate flowers arranged             in terminal and axillary panicles; freely flowering habit             with typically about five flowers per panicle; flowers             facing outwardly to nodding.         -   Fragrance.—None detected.         -   Natural flowering season.—Plants begin flowering about ten             months after planting; plants flower from late autumn into             the winter in Germany.         -   Flower longevity on the plant.—About ten days; flowers             persistent.         -   Inflorescence height.—About 16.2 cm.         -   Inflorescence diameter.—About 14.1 cm.         -   Flower buds.—Length: About 1.8 cm. Diameter: About 1 cm.             Shape: Ovate. Color: Close to 145B to 145C.         -   Flower diameter.—About 6.7 cm.         -   Flower depth (height).—About 3 cm.         -   Petals.—Quantity and arrangement: About 15 arranged in             several whorls. Length: About 3 cm. Width: About 1.8 cm.             Shape: Ovate. Apex: Acute to abruptly acute. Margin: Entire,             undulate. Texture, upper and lower surfaces: Smooth,             glabrous; slightly velvety. Color: When opening, upper and             lower surfaces: Close to 157D; towards the base, close to             149D. Fully opened, upper and lower surfaces: Close to             NN155B; towards the base, close to 149D; with development,             color becomes closer to 149D.         -   Sepals.—Quantity and arrangement: Five arranged in a single             whorl. Length: About 3.6 cm. Width: About 3.7 cm. Shape:             Broadly ovate to orbicular. Apex: Rounded to obtuse. Base:             Cuneate. Margin: Entire, undulate. Texture, upper and lower             surfaces: Smooth, glabrous. Color: When opening and fully             opened, upper surface: Close to 157D; towards the base,             close to 145C; color becoming closer to 144C with             development. When opening and fully opened, lower surface:             Close to 145A to 145D.         -   Peduncles.—Length: About 25.2 cm. Diameter: About 5 mm to             7 mm. Strength: Strong. Aspect: About 10° from vertical.             Texture: Smooth, glabrous. Color: Close to 144B to 144C.         -   Pedicels.—Length: About 4.8 cm. Diameter: About 3 mm.             Aspect: About 30° from peduncle axis. Strength: Moderately             strong. Texture: Smooth, glabrous. Color: Close to 144A to             144B.         -   Reproductive organs.—Stamens: Quantity per flower:             About 100. Filament length: About 1.4 cm. Filament color:             Close to 157D. Anther shape: Reniform, flattened. Anther             length: About 2.5 mm. Anther color: Close to 150D. Pollen             amount: Scarce. Pollen color: Close to 4D. Pistils: Quantity             per flower: About four or five. Pistil length: About 1.1 cm.             Stigma shape: Club-shaped. Stigma color: Close to 157D.             Style length: About 1 cm. Style color: Close to 150D. Ovary             color: Close to 150C to 150D.         -   Seeds and fruits.—Seed and fruit development have not been             observed on plants of the new Helleborus. -   Garden performance: Plants of the new Helleborus have been observed     to have good garden performance and to tolerate rain, wind, high     temperatures of about 35° C. and are hardy to USDA Hardiness Zone 5. -   Pathogen & pest resistance: Plants of the new Helleborus have not     been observed to be resistant to pathogens and pests common to     Helleborus plants. 

It is claimed:
 1. A new and distinct Helleborus plant named ‘NVDH 100’ as illustrated and described. 